1. Field of the Invention
The present invention relates to a system and a method for controlling traveling direction of an aircraft. In particular, the present invention relates to a system and a method for controlling traveling direction of an aircraft, in which traveling direction control of an aircraft in flight is easily performed, and in which operations for directional change of an aircraft on the ground can easily be performed.
2. Description of the Related Art
In general, the following controls are performed when steering an aircraft. That is, referring to FIG. 15, a pilot performs pitching control of the aircraft by operating an elevator 91 mounted to a horizontal tail in accordance with moving a control stick 90 in a cockpit in a direction toward the front or rear of the airframe, to thereby nose up or nose down. A pilot performs rolling control of the aircraft in right and left directions by operating right and left ailerons 92 mounted to main wings in accordance with moving the control stick 90 in a cockpit in a direction toward the right or left of the airframe. Furthermore, a pilot performs yawing control of the aircraft in a rotational direction by operating a ruder 95 mounted a vertical tail by stepping on a pair of right and left rudder pedals 93 and 94 using their foot in a cockpit.
When the aircraft has landed, the pilot puts the brakes on the aircraft by actuating brakes 96 and 97 for braking landing gear wheels, which is effected by stepping on the rudder pedals 93 and 94, similar to operating a brake pedal in an automobile, thereby slows down the aircraft.
In this case, once the aircraft has been decelerated to a predetermined speed after it has landed, it is necessary to change the direction of travel of the aircraft when moving it to a necessary location within an airport for parking or the like. Here, the pilot applies braking to either the left or the right wheels by stepping on either the rudder pedal 93 or 94, and the aircraft thus turns toward the direction in which braking is applied, thereby changing the direction of travel of the aircraft.
In all present-day aircraft, regardless of whether they are large size aircraft such as a long-range jet, fighter, or small size aircraft such as a Cessna, either one of the pair of right and left rudder pedals is operated by stepping on it as stated above when it becomes necessary to change the direction of the aircraft that is moving at a predetermined speed on the ground after landing or before takeoff. Directional changes of the aircraft are performed when moving on the ground before takeoff or after landing by thus performing braking operations to either the right or left side wheels. The workload required by the pilot in steering can be reduced, if such aircraft direction change operation can be performed without using the pair of right and left rudder pedals.
Furthermore, autopilot systems are installed in large size aircraft such as a long-range jet. The autopilot system is one in which control of traveling direction of the aircraft in flight is performed automatically by an apparatus, including yawing control performed by an auto rudder mechanism that automatically performs the aforementioned rudder operations. This type of autopilot system has not yet become popular for small aircraft such as a Cessna, and therefore it is necessary for the pilot to manually perform yawing control by operating the rudder pedals in flight.
This type of yawing control of the aircraft effected by operating the rudder pedals 93 and 94 prevents the altitude from dropping while the aircraft slips in a horizontal direction when the airframe is turning or when it is tilted due to a strong wind, so-called xe2x80x9cside slipxe2x80x9d, for example. Thus the aircraft is turned in a stable state. And the traveling direction control of the aircraft is performed to ensure a correct traveling direction by suitably moving the rudders. These are essential operations in controlling the direction of travel of the aircraft.
However, the sensibility as a human of a pilot with respect to such sideslip of aircraft is very delicate. An extremely large amount of time is required during training in mastering this as a pilot, and it is necessary to perform rudder operations based upon this delicate sensibility by stepping on the rudder pedals 93 and 94. Yawing control operations using the rudders are therefore extremely complex for the pilot.
Consequently, it has long been desired to lower the load placed upon the pilot during control by automating such yawing control of the aircraft that uses rudder operations.
An object of the present invention is to reduce the workload of a pilot relating to aircraft control.
Furthermore, another object of the present invention is to perform automatic braking and directional change of an aircraft after landing and before takeoff, thereby reducing the workload on a pilot relating to aircraft steering after landing and before takeoff.
In addition, another object of the present invention is to prevent malfunction of a braking mechanism when changing the direction of an aircraft after landing and before takeoff, thus performing braking and directional change of aircraft safely and surely.
Another object of the present invention is to reduce the workload of a pilot on an aircraft, in particular a small aircraft, which is required for yawing control in steering in flight, and by combining this with each of the aforementioned objects, reducing the workload on a pilot for controlling an aircraft by using his or her feet.
In order to accomplish these objectives, the present invention is structured such that control of traveling direction is performed automatically using a yaw damper mechanism in flight, and when braking of an aircraft in motion on the ground is performed, that braking is performed by operating onexe2x80x94single brake pedal provided in cockpit and capable of controlling the braking of the aircraft. Further, control of traveling direction of an aircraft is performed by automatically generating a larger braking force for landing gear wheels on a side toward which the aircraft will change direction as compared with that applied to landing gear wheels on the other side, when performing directional change of an aircraft on the ground.
The present invention is structured such that braking control is automatically performed when an aircraft is traveling at a speed equal to or greater than a predetermined speed after an aircraft has landed. And thus if the speed of the aircraft has been reduced to less than the predetermined speed, then a braking force is generated to landing gear wheels on a side toward which the aircraft will change direction, which is larger than the braking force generated to landing gear wheels on the other side. Control of traveling direction of the aircraft is thus performed.
In addition, the present invention is structured such that the speed of the aircraft is increased during directional change of the aircraft by automatically generating engine thrust, thus making directional change possible in a short time, for cases in which, as described above, control of traveling direction is performed by generating a braking force for landing gear wheels on a side toward which the aircraft will change direction which is larger than the braking force acting on the landing gear wheels on the other side.
In view of the above, according to a first aspect of the present invention, there is provided a system for controlling traveling direction of an aircraft that is installed with a pair of landing gear on right and left sides of its air frame. When operating a control stick in right or left directions of the airframe, a larger braking force is applied to landing gear wheels mounted on a side toward which a control stick is operated, as compared with a braking force acting on landing gear wheels mounted on the other side.
Therefore, according to the present invention, if the control stick is operated to either the right or left side direction of the airframe of the aircraft, a larger braking force acts on one side of the landing gear, in the direction of which the control stick is operated, than that acting on landing gear on the other side. The aircraft thus turns in the direction to which the control stick is operated.
As a result, control of traveling direction of an aircraft can also be performed on the ground, in working together with the operation of the control stick, according to the present invention.
According to a second aspect of the present invention, there is provided a system for controlling traveling direction of an aircraft that is installed with a plurality of landing gear on right and left sides of its airframe. The system for controlling traveling direction comprises a detection means capable of detecting an operation state of a control stick, and a braking mechanism capable of supplying braking force to each of the plurality of landing gear wheels on the right and left sides. A larger braking force is supplied by the braking mechanism to landing gear wheels on a side toward a direction of which the control stick is operated than is supplied to landing gear wheels on the other side, based upon the operation state of the control stick detected by the detection means, for cases in which the control stick is operated toward the right and left side directions of the airframe.
Further, according to a third aspect of the present invention, a single brake pedal is installed within a cockpit of an aircraft, which is capable of performing braking of a pair of landing gear wheels mounted on the right and left sides of the airframe. Braking of the aircraft is performed by operating the single brake pedal.
Therefore, according to the present invention, braking of the aircraft can be performed by a pilot stepping on the single brake pedal if braking of the aircraft is necessary when in motion on the ground.
Steering control of the aircraft on the ground can therefore be made easier, because it is not needed to be performed braking operations of the aircraft by stepping on the pair of right and left side brake pedals with both feet, as is performed conventionally.
According to a fourth aspect of the present invention, for cases in which a detection means that is capable of detecting the operation state of the control stick detects flare out operation as an aircraft lands, braking of a plurality of landing gear wheels mounted on the right and left sides of an airframe is performed on condition that flare out operation of a control stick was taken.
The term xe2x80x9cflare outxe2x80x9d operation refers to an operation performed by pulling the control stick toward the pilot side in order to pull up a nose when the aircraft is landed.
Therefore, according to the present invention, braking force is supplied to right and left landing gear wheels, if flare out operation of the control stick is performed in order to pull up the nose by the pilot when the aircraft is landed taken as a prerequisite condition, and the aircraft is thus braked. As a result, according to the present invention, braking operations using the control stick become possible, without performing braking operations effected by the pilot stepping on rudder pedals as is conventionally done.
Steering control of the aircraft is therefore made even easier because directional change of the aircraft becomes possibly by the pilot operating only the control stick during a period from landing until parking the aircraft. And thus the load required to control the aircraft, when landing and after landing, can be reduced.
Further, although the aforementioned flare out operations of the control stick are also performed when the aircraft takes off, braking the plurality of the landing gear wheels mounted on the right and left sides of the airframe is not performed.
Moreover, According to a fifth aspect of the present invention, the system is further provided with detection means capable of detecting the speed of an aircraft. A larger braking force can be made to act on landing gear wheels on a side toward which a control stick is operated, as compared with that acting on landing gear wheels on the other side, for cases in which the aircraft=speed of the aircraft is judged to be equal to or less than a predetermined speed based upon speed information detected by the detection means.
Here, the term xe2x80x9cpredetermined speedxe2x80x9d refers to both xe2x80x9cairspeedxe2x80x9d and xe2x80x9cground speedxe2x80x9d. The term xe2x80x9cairspeedxe2x80x9d refers to a relative speed of an aircraft with respect to the surrounding air, measured by a Pitot-Static System installed in the airframe of the aircraft. Further, the term xe2x80x9cground speedxe2x80x9d denotes a relative speed of the aircraft with respect to the surface of the ground. The aircraft speed is basically judged by the ground speed, but the speed of the aircraft_may also be measured using the airspeed. In addition, the term xe2x80x9cpredetermined speedxe2x80x9d as described herein specifically refers to a speed on the order of 20 km/hr.
Therefore, in accordance with the present invention, when the aircraft moves at a speed equal to or less than the predetermined speed on the ground, then a larger braking force acts on landing gear wheels on the side toward which the control stick is operated than acts on the landing gear wheels on the side toward which the control stick is not operated, if the pilot operates the control stick toward the right or left side of the airframe when heading for a parking area.
As a result, according to the present invention, with a prerequisite condition that a speed of the aircraft has reached a predetermined speed, braking control is performed for changing the direction of travel of the aircraft by operating the control stick, and then the direction of travel of the aircraft changes to the direction in which the control stick is operated.
Further, a larger braking force acts on the landing gear on the side toward which the control stick is operated than that on the other side, only when the aircraft speed is equal to or less than a predetermined speed. Therefore, for example, if the aircraft lands while receiving a cross wind, then the aircraft descends while being maintained in balance by the control stick being operated in the right or left direction. In this situation, since the speed of the aircraft is equal to or greater than a predetermined value, an unstable situation in which, for example, the aircraft touches down at landing while braking is being applied to either of the pair of landing gear wheels can be prevented.
In accordance with a sixth aspect of the present invention, the system further comprises the detection means capable of detecting the housing state of a landing gear housing. If it is determined the landing gear to be projected from an airframe based on information detected by the detection means, then a larger braking force is made to act on landing gear wheels on a side toward which a control stick is operated, as compared with that acting on landing gear wheels on the other side.
Therefore, according to the prevent invention, if an aircraft is of a type in which the landing gear is housed within the airframe, for example, with a prerequisite condition that that the landing gear has been projected from the fuselage or the main wing and thus a condition for landing has been made, a larger braking force is made to act on the landing gear wheels on the side toward which the control stick is operated than that on the other side.
In accordance with a seventh aspect of the present invention, the system comprises a detection means capable of detecting a speed of the aircraft and a detection means capable of detecting a landing gear housing state. A larger braking force can act on landing gear wheels on a side toward which a control stick is operated than that acting on landing gear wheels on the other side, when it is determined that the landing gear is projected from the airframe and the aircraft travels at or below the predetermined speed, based upon information from both of the detection means.
Therefore, in accordance with the present invention, Control of directional change is preformed based on the condition that landing gear is projected from the airframe and the speed of the aircraft is equal to or less than the predetermined speed.
As a result, according to the present invention, when the aircraft has landed and has been braked while running on the ground such that its speed is decelerated to equal to or less than the predetermined speed, the larger braking force acts on landing gear wheels disposed on the side toward which a pilot wants to change direction by operating the control stick than the braking force acting on the landing gear wheels on the other side. Change of direction thus becomes possible toward the side applied with larger braking force.
In accordance with an eighth aspect of the present invention, the system further comprises the detection means capable of detecting engine throttle opening. For cases in which it is determined that the engine throttle opening is equal to or less than a predetermined value based on information output from the detection means, a larger braking force can apply to landing gear wheels on a side toward which a control stick is operated than the braking force applied to landing gear wheels on the other side.
Therefore, according to the present invention, determination of whether or not to perform direction change control is made based on whether or not the throttle opening is equal to or less than a predetermined value.
In addition to the judging condition based on the speed of the aircraft, the judging condition based on the throttle opening can be used as an independent condition. The throttle opening is small at landing, and the throttle opening is large at takeoff. In addition, braking control of the aircraft is not necessary when takeoff.
Therefore, if the judgment condition relating to the throttle opening is thus used as an independent condition in addition to the judgment condition relating to the speed of the aircraft, then braking control will not be performed on the aircraft when the throttle opening is larger than a predetermined value.
In accordance with a ninth aspect of the present invention, the system further comprises detection means capable of detecting aircraft engine manifold pressure. A larger braking force can be made to act on landing gear wheels on a side toward which a control stick is operated as compared with that applied to landing gear wheels on the other side, for cases in which the manifold pressure is determined to be equal to or less than a predetermined value based on information detected by the manifold pressure detection means.
According to the present invention, therefore, the aircraft is determined to have landed when the engine manifold pressure is equal to or less than a predetermined value, because the engine power has also become lower in such a case. Braking control of the aircraft is then performed.
In this case the judgment condition relating to whether or not the engine manifold pressure is equal to or less than a predetermined value, and the judgment condition relating to whether or not the throttle opening is equal to or less than a predetermined value can be provided independent of each other. If the judgment condition relating to whether or not the engine manifold pressure is equal to or less than a predetermined value, and the judgment condition relating to whether or not the throttle opening is equal to or less than a predetermined value are thus made independent of each other, then the landing state of the aircraft is determined and braking control can appropriately be performed even when the detection means for detecting throttle opening is operating incorrectly. A fail-safe system can be thus attained, and simplification of aircraft control and safety of aircraft control can both be achieved.
In accordance with a tenth aspect of the present invention, a working pressure supplied to a braking mechanism for landing gear wheels mounted on a side to which a control stick is operated is larger than a working pressure supplied to a braking mechanism for landing gear wheels mounted on the side opposite to the side to which the control stick is operated.
Therefore, according to the present invention, when the control stick is operated, a larger braking force acts on the wheels of the landing gear installed on the side to which the aircraft is to turn, as compared with the braking force acting on the wheels of the landing gear installed on the opposite side. The aircraft then thus changes direction to the direction in which the control stick is operated.
In accordance with an eleventh aspect of the present invention, the working pressure applied to a braking mechanism for landing gear wheels mounted on a side that is opposite to the side to which a control stick is operated is set to become less than the working pressure applied to a braking mechanism for landing gear wheels mounted on the side to which the control stick is operated, if the single brake pedal mentioned above has been stepped on and the speed of an aircraft has become equal to or less than the predetermined speed.
Therefore, according to the present invention, a smaller braking force acts on the landing gear wheels mounted on the side that is opposite to the side to which the airframe is to turn, as compared with the braking force acting on the landing gear wheels mounted on the side to which the airframe is to turn, for cases in which braking has been performed by stepping on the single brake pedal while the pilot also operates the control stick. As a result, the braking force acting on the landing gear wheels on the side to which the control stick is operated becomes larger than that on the other side, and the aircraft changes direction to the direction in which the control stick is operated.
According to a twelfth aspect of the present invention, the detection means for detecting the stepping operation of the single brake pedal is provided. The working pressure applied to a braking mechanism for landing gear wheels mounted on a side that is opposite to the side toward which a control stick is operated is set to become lower than the working pressure applied to a braking mechanism acting on landing gear wheels mounted on the side to which the control stick is operated, when it is determined by the detection means that the brake pedal has been stepped on and braking has been thus effected.
Therefore, according to the present invention, the lower working pressure is supplied to the braking mechanism for the landing gear wheels mounted to the side opposite to the direction in which the control stick is operated than the working pressure supplied to the braking mechanism for the landing gear wheels mounted on the side to which the control stick is operated, with_the condition that the single brake pedal has been stepped on.
As a result, the fact that the brake pedal has been stepped on in order to actuate the braking mechanisms is additionally taken as a condition, compared to the case of actuating the braking mechanisms based solely on the predetermined speed. Therefore a situation such that when the detection means for detecting the speed of the aircraft is not operating correctly, for example, braking mechanism are actuated while performing directional change, at a speed higher than the speed at which the braking mechanisms must be actually actuated so that the aircraft is placed in an unstable state, can be prevented. An automatic directional change control of the airframe can thus be more safely performed.
Further, according to a thirteenth aspect of the present invention, the engine throttle opening is controlled to become larger when a braking force acting on landing gear wheels mounted on a side to which a control stick is operated is larger than the braking force acting on landing gear wheels mounted on the opposite side, based upon information from the detection means capable of detecting operation of the control stick.
Therefore, according to the present invention, the speed during directional change of an aircraft is increased and quick directional change thus becomes possible, because the engine throttle opening is made larger and a thrust force is increased thereby, when the braking force acting on the landing gear wheels mounted on the side to which the control stick is operated becomes larger than the braking force acting on the landing gear wheels mounted on the opposite side to thereby effect the directional change.
According to a fourteenth aspect of the present invention, a single braking pedal capable of supplying braking force to the wheels installed on landing gear is mounted within a cockpit of an aircraft instead of rudder pedals, and a yaw damper mechanism is installed in an aircraft so that automatic yawing control is performed by a rudder installed in a vertical stabilizer of the aircraft while the aircraft is in flight.
According to the present invention, conventional rudder pedals are not provided in the cockpit but the single brake pedal is installed instead. Braking operation after landing is therefore performed by operating the single brake pedal, and yawing control in fright is performed by automatically controlling the rudder on the vertical stabilizer by using of the yaw damper mechanism.
As a result, it is not necessary for a pilot to perform rudder operations using conventional rudder pedals in order to perform yawing control in flight, and the amount of time required for mastering rudder pedal operations can be eliminated. In addition, braking a plurality of landing gear wheels mounted on the right and left sides of the airframe can be performed by operating the single brake pedal when the aircraft is moving or taxing on the ground. The workload on the pilot for aircraft control operations can thus be greatly reduced.
According to a fifteenth aspect of the present invention, the detection means capable of detecting the operation state of a control stick is capable of detecting the direction in which control stick is operated as well as the amount of which control stick is operated. Braking force is applied to braking mechanisms for wheels mounted to the landing gear on the right and lift sides of an airframe, based upon information relating to the direction in which the control stick is operated and the amount of which the control stick is operated if the control stick is operated to the right or left side of the airframe.
Therefore, according to the present invention, the detection means detects the direction in which the control stick is operated and the amount of which the control stick is operated when a pilot has operated the control stick by a predetermined angle in a direction to the right or left side of the airframe. Braking force is then applied to braking mechanisms for the landing gear wheels mounted on the right and left sides of the airframe based upon information relating to the detected direction in which the control stick is operated and amount of which the control stick is operated.
Therefore, according to the present invention, a suitable amount of braking force can thus be supplied to the landing gear wheels on the side to which the control stick is operated, corresponding to the amount of control stick operation. The pilot can therefore made directional changes of the aircraft by a desired angular amount, in the right or left directions in which the pilot wants to change.
According to a sixteenth aspect of the present invention, there is provided a method of controlling a direction of travel of an aircraft that is installed with a plurality of landing gear on the right and left sides of its airframe, the method comprising the steps of: detecting a direction of operation and an amount of operation of a control stick which is performed by a pilot in a direction to the right or left side of the airframe; detecting the speed of the aircraft; and determining whether or not the speed of the aircraft is equal to or less than a predetermined value. If the speed of the aircraft is less than or equal to the predetermined value, the method further comprises the following steps of: determining, based on the direction of operation of the control stick, to which side of the aircraft the direction of travel is to be changed; computing an amount of brake operation based on the amount of operation of the control stick; and supplying the computed amount of braking to landing gear wheels mounted on the side of the airframe to which the direction of travel is to be changed.
Further, according to a seventeenth aspect of the present invention, there is provided a method of controlling the direction of travel of an aircraft, further comprising a step of detecting a displacement direction and a displacement amount of the aircraft in a yawing direction of the airframe. The method further comprises, if it is determined that the speed of the aircraft is larger than the predetermined value, the step of computing an amount of rudder operation based on the displacement direction and the displacement amount of the aircraft in the yawing direction, and then operating the rudder based on the amount of rudder operation.
According to an eighteenth aspect of the present invention, there is provided a method of controlling the direction of travel of an aircraft, further comprising a step of computing an amount of throttle opening increase based upon the direction and the amount of the control stick operation by the pilot in the right or left directions of the airframe. For cases in which the computed amount of braking operation is supplied to the landing gear wheels on the side to which the aircraft is to change its direction of travel, the throttle opening is controlled based on the computed amount of throttle opening increase.
According to a nineteenth aspect of the present invention, there is provided a method of controlling direction of travel of an aircraft to which a plurality of landing gear wheels are installed on the right and left sides of an airframe, the method comprising the steps of: detecting a direction of operation and an amount of operation of a control stick performed by a pilot in a direction to the right or left side of the airframe; detecting the speed of the aircraft; detecting that braking operations have been performed by the pilot; and determining whether or not the speed of the aircraft is equal to or less than a predetermined value. Method further comprises the steps of: determining, based on the direction of operation of the control stick, to which side of the aircraft the direction of travel is to be changedxe2x80x94for cases in which the speed of the aircraft is less than or equal to the predetermined value and if it is detected that the above braking operations have been performed; computing an amount of braking pressure reduction based on the amount of operation of the control stick, if the above braking operations have been performed; and supplying the computed amount of braking pressure reduction to landing gear wheels mounted on the side of the airframe that is opposite to the side to which the direction of travel is to be changed.
According to a twentieth aspect of the present invention, there is provided a method of controlling direction of travel of an aircraft to which a plurality of landing gear are installed on the right and left sides of an airframe, further comprising a step of computing the amount of throttle opening increase based on the direction and amount of the control stick operation performed by a pilot in the right or left direction of the airframe. A throttle opening is controlled based on the computed throttle opening increase amount when the computed amount of braking pressure reduction is supplied to the landing gear wheels mounted on the side of the airframe that is opposite to the side to which the direction of travel is to be changed.
According to a twenty-first aspect of the present invention, there is provided a method of controlling direction of travel of an aircraft that is installed with a plurality of landing gear on the right and left sides of its airframe, the method further comprising the steps of: detecting an amount of flare out operation of the control stick by the pilot; detecting a throttle opening; determining whether or not the throttle opening is equal to or larger than a predetermined value; and computing an amount of braking operation based on the amount of flare out operation when the throttle opening is equal to or less than a predetermined value and the speed of the aircraft is equal to or greater than a predetermined value. The computed amount of braking operation is supplied to all of the landing gear wheels mounted on the right and left sides of the airframe.
According to a twenty-second aspect of the present invention, there is provided a method of controlling direction of travel of an aircraft to which a plurality of landing gear are installed on the right and left sides of an airframe, the method further comprising the steps of: detecting engine manifold pressure; determining whether or not the throttle opening is equal to or greater than a predetermined value; determining whether or not the engine manifold pressure is equal to or less than a predetermined value for cases in which the throttle opening is judged to be equal to or larger than the predetermined value; and computing an amount of braking operation based on the amount of flare out for cases in which the throttle opening is equal to or larger than the predetermined value of throttle opening, the engine manifold pressure is equal to or less then the predetermined value of engine manifold pressure, and the speed of the aircraft_is equal to or larger than a predetermined value. The computed amount of braking operation is supplied to all of the landing gear wheels mounted on the right and left sides of the airframe.